<template>
    <!-- ref获取dom的数据 -->
    <div class="list" ref="wrapper">
        <div>
            <div class="area">
                <div class="title border-topbottom">当前城市</div>
                <div class="button-list">
                    <div class="button-wrapper">
                        <div class="button">{{this.currentCity}}</div>
                    </div>
                </div>
            </div>
            <div class="area">
                <div class="title border-topbottom">热门城市</div>
                <div class="button-list">
                    <div class="button-wrapper" v-for="item of hot" :key="item.id" @click="handleCityClick(item.name)">
                        <div class="button">{{item.name}}</div>
                    </div>
                </div>
            </div>
            <div class="area"
                v-for="(item, key ) of cities" 
                :key="key"
                :ref="key"
                 >
                <div class="title border-topbottom">{{key}}</div>
                <div class="item-list">
                    <div class="item border-bottom"
                         v-for="innerItem of item " :key="innerItem.id" 
                          @click="handleCityClick(innerItem.name)"
                         >  
                         {{innerItem.name}}
                    </div>
                </div>
            </div>
        </div>
    </div>
</template>

<script>
import  Bscroll from 'better-scroll'
import  {mapState,mapMutations} from 'vuex'
export default{
    name: 'CityListist',
    props: {
        hot : Array,
        cities: Object,
        letter: String
    },
    //页面挂载完毕之前执行
    mounted () {
        //获取dom的节点数据 $.refs.wrapper 传入 Bscroll对象中
        this.scroll= new Bscroll(this.$refs.wrapper)
    },
    //监听器
    watch: {
        //监听letter变化就执行
        letter () {
            // console.log("letter变化："+this.letter)
            if(this.letter){
                //dom数据返回是数组，因为:ref循环绑定是key值
                const element = this.$refs[this.letter][0]
                this.scroll.scrollToElement(element);
            }
        }
    },
    methods :{
        handleCityClick(name){
            // this.$store.dispatch('changeCity',name);
            // 利用js实现路由跳转
            this.$router.push('/');
            //也可以跳过actions直接修改
            // this.$store.commit('changeCity',name)
            this.changeCity(name)
        },
        //替换 this.$store.commit('changeCity',name)
        ...mapMutations(['changeCity'])
    },
    computed: {
        ...mapState({
          currentCity: 'city'
      })
    }

}  
</script>

<style lang="stylus" scoped>
    @import  '~styles/varibles.styl'

    .border-topbottom 
        &:before 
            border-color: #ccc
        &:after
            before-color: #ccc

    .border-bottom 
        &:before 
            border-color: #ccc

    .list
        overflow: hidden
        position: absolute
        top: 1.58rem 
        left: 0
        right: 0
        bottom: 0
        .title
            line-height: .54rem 
            background: #eee 
            padding-left: .2rem 
            color: #666
            font-size: .26rem 
        .button-list
            overflow: hidden
            padding: .1rem  .6rem .1rem .1rem
            .button-wrapper
                float: left
                width: 33.33%
                .button
                    margin: .1rem 
                    padding: .1rem 0
                    text-align: center 
                    border: .02rem solid #ccc
                    border-radius: .06rem 
        .item-list
            .item
                line-height: .76rem 
                padding-left: .2rem 

</style>